Determining gas and liquid flow rates in a multi-phase flow

Abstract

A method and apparatus for determining gas and liquid flow rates in a multi-phase flow are provided. In accordance with one embodiment of the present invention, a method of determining gas and liquid flow rates in a multi-phase flow is provided. The method utilizes a set of gas phase ultrasonic transducers and a set of liquid phase ultrasonic transducers positioned to direct ultrasonic signals through the multi-phase flow. The method comprising the steps of: (i) establishing a set of gas phase control parameters and a gas phase algorithm for determining a flow rate of a gaseous portion of the multi-phase flow, wherein the gas phase control parameters define a gas phase ultrasonic signal characterized by a gas phase center frequency and a gas phase bandwidth and the gas phase algorithm comprises at least one of a gas phase transit time algorithm and a gas phase cross correlation algorithm; (ii) establishing a set of liquid phase control parameters and a liquid phase algorithm for determining a flow rate of a liquid portion of the multi-phase flow, wherein the liquid phase control parameters define a liquid phase ultrasonic signal characterized by a liquid phase center frequency and a liquid phase bandwidth and the liquid phase algorithm comprises a liquid phase cross correlation algorithm; (iii) controlling the gas phase ultrasonic transducers according to the gas phase control parameters so as to transmit the gas phase ultrasonic signal; (iv) analyzing the gas phase ultrasonic signal according to the gas phase algorithm; (v) controlling the liquid phase ultrasonic transducers according to the liquid phase control parameters so as to transmit a liquid phase ultrasonic signal; (vi) analyzing the liquid phase ultrasonic signal according to the liquid phase algorithm; and (vii) determining the gas and liquid flow rates based upon the analyses of the gas phase ultrasonic signal and the liquid phase ultrasonic signal.

What is claimed is:  
     
       1. A method of determining gas and liquid flow rates in a multi-phase flow utilizing a set of gas phase ultrasonic transducers and a set of liquid phase ultrasonic transducers positioned to direct ultrasonic signals through said multi-phase flow, said method comprising the steps of, 
       establishing a set of gas phase control parameters and a gas phase algorithm for determining a flow rate of a gaseous portion of said multi-phase flow, wherein  
       said gas phase control parameters define a gas phase ultrasonic signal characterized by a gas phase center frequency and a gas phase bandwidth and  
       said gas phase algorithm comprises at least one of a gas phase transit time algorithm and a gas phase cross correlation algorithm and wherein said gas phase algorithm is established said gas phase cross correlation algorithm over said gas phase transit time algorithm as a function of an amount of liquid in said multi-phase flow;  
       establishing a set of liquid phase control parameters and a liquid phase algorithm for determining a flow rate of a liquid portion of said multi-phase flow, wherein  
       said set of liquid phase control parameters are established separately from said set of gas phase control parameters and  
       said liquid phase control parameters define a liquid phase ultrasonic signal characterized by a liquid phase center frequency and a liquid phase bandwidth and  
       said liquid phase algorithm comprises a liquid phase cross correlation algorithm;  
       controlling said gas phase ultrasonic transducers according to said gas phase control parameters so as to transmit said gas phase ultrasonic signal;  
       analyzing said gas phase ultrasonic signal according to said gas phase algorithm;  
       controlling said liquid phase ultrasonic transducers according to said liquid phase control parameters so as to transmit a liquid phase ultrasonic signal, wherein said liquid phase ultrasonic transducers am controlled separately from said gas phase ultrasonic transducers;  
       analyzing said liquid phase ultrasonic signal according to said liquid phase algorithm; and  
       determining said gas and liquid flow rates based upon said analyses of said gas phase ultrasonic signal and said liquid phase ultrasonic signal.  
     
     
       2. A method of determining gas and liquid flow rates in a multi-phase flow as claimed in  claim 1  further comprising the steps of: 
       establishing said gas phase control parameters for a plurality of sets of said gas phase ultrasonic transducers such that said gas phase control parameters define a plurality of gas phase ultrasonic signals;  
       establishing said liquid phase control parameters for a plurality of sets of said liquid phase ultrasonic transducers such that said liquid phase control parameters define a plurality of liquid phase ultrasonic signals; and  
       analyzing said gas phase and said liquid phase ultrasonic signals with the aid of an ultrasonic data selection terminal, wherein said ultrasonic data selection terminal is controlled so as to establish a dwell time for each set of said plurality of sets of ultrasonic transducers.  
     
     
       3. A method of determining gas and liquid flow rates in a multi-phase flow as claimed in  claim 2  wherein said dwell time is between about one second and about five seconds. 
     
     
       4. A method of determining gas and liquid flow rates in a multi-phase flow as claimed in  claim 1  further comprising the step of establishing said gas phase control parameters for a plurality of sets of said gas phase ultrasonic transducers such that said gas phase control parameters define a plurality of gas phase ultrasonic signals. 
     
     
       5. A method of determining gas and liquid flow rates in a multi-phase flow as claimed in  claim 4  further comprising the step of analyzing said gas phase ultrasonic signals with the aid of an ultrasonic data selection terminal, wherein said ultrasonic data selection terminal is controlled so as to establish a dwell time for each set of said plurality of sets of said gas phase ultrasonic transducers. 
     
     
       6. A method of determining gas and liquid flow rates in a multi-phase flow as claimed in  claim 5  wherein said dwell time is between about one second and about five seconds. 
     
     
       7. A method of determining gas and liquid flow rates in a multi-phase flow as claimed in  claim 1  further comprising the step of establishing said liquid phase control parameters for a plurality of sets of said liquid phase ultrasonic transducers such that said liquid phase control parameters define a plurality of liquid phase ultrasonic signals. 
     
     
       8. A method of determining gas and liquid flow rates in a multi-phase flow as claimed in  claim 7  further comprising the step of analyzing said liquid phase ultrasonic signals with the aid of an ultrasonic data selection terminal, wherein said ultrasonic data selection terminal is controlled so as to establish a dwell time for each set of said plurality of sets of said liquid phase ultrasonic transducers. 
     
     
       9. A method of determining gas and liquid flow rates in a multi-phase flow as claimed in  claim 8  wherein said dwell time is between about one second and about five seconds. 
     
     
       10. A method of determining gas and liquid flow rates in a multi-phase flow as claimed in  claim 1  further comprising the step of analyzing said liquid phase ultrasonic signals according to a plurality of liquid phase algorithms with the aid of an ultrasonic data selection terminal, wherein said ultrasonic data selection terminal is controlled so as to establish a dwell time for each algorithm of said plurality of liquid phase algorithms. 
     
     
       11. A method of determining gas and liquid flow rates in a multi-phase flow as claimed in  claim 1  further comprising the step of analyzing said gas phase ultrasonic signals according to a plurality of gas phase algorithms with the aid of an ultrasonic data selection terminal, wherein said ultrasonic data selection terminal is controlled so as to establish a dwell time for each algorithm of said plurality of gas phase algorithms. 
     
     
       12. A method of determining gas and liquid flow rates in a multi-phase flow as claimed in  claim 1  further comprising the step of analyzing said liquid phase ultrasonic signals according to a plurality of sets of liquid phase control parameters with the aid of an ultrasonic data selection terminal, wherein said ultrasonic data selection terminal is controlled so as to establish a dwell time for each set of said plurality of sets of liquid phase control parameters. 
     
     
       13. A method of determining gas and liquid flow rates in a multi-phase flow as claimed in  claim 1  further comprising the step of analyzing said gas phase ultrasonic signals according to a plurality of sets of gas phase control parameters with the aid of an ultrasonic data selection terminal, wherein said ultrasonic data selection terminal is controlled so as to establish a dwell time for each set of said plurality of sets of gas phase control parameters. 
     
     
       14. A method of determining gas and liquid flow rates in a multi-phase flow as claimed in  claim 1  wherein said method further comprises the step of establishing said set of liquid phase control parameters and said liquid phase algorithm for determining a film thickness of said liquid portion of said multi-phase flow, and wherein said liquid phase algorithm further comprises a liquid phase pulse echo mode algorithm. 
     
     
       15. A method of determining gas and liquid flow rates in a multi-phase flow as claimed in  claim 1  wherein said step of establishing said gas phase algorithm is characterized by a preference for said gas phase cross correlation algorithm over said gas phase transit time algorithm as an amount of liquid in said multi-phase flow increases. 
     
     
       16. A method of determining gas and liquid flow rates in a multi-phase flow as claimed in  claim 1  wherein: 
       said multi-phase flow is contained within a pipeline;  
       said gas phase ultrasonic signal is transmitted by coupling said set of gas phase ultrasonic transducers to an exterior surface of said pipeline; and  
       said liquid phase ultrasonic signal is transmitted by coupling said set of liquid phase ultrasonic transducers to said exterior surface of said pipeline.  
     
     
       17. A method of determining gas and liquid flow rates in a multi-phase flow as claimed in  claim 1  wherein: 
       said multi-phase flow is contained within a pipeline;  
       said gas phase ultrasonic signal is transmitted by coupling said set of gas phase ultrasonic transducers to an exterior surface of said pipeline;  
       said set of gas phase ultrasonic transducers comprise at least one upstream gas phase ultrasonic transducer and at least one downstream gas phase ultrasonic transducer positioned on opposite sides of a central longitudinal axis of said pipeline;  
       said liquid phase ultrasonic signal is transmitted by coupling said set of liquid phase ultrasonic transducers to an exterior surface of said pipeline;  
       said set of liquid phase ultrasonic transducers comprise at least one upstream of liquid phase ultrasonic transducer and at least one downstream liquid phase ultrasonic transducer positioned on a common side of said central longitudinal axis of said pipeline.  
     
     
       18. A method of determining gas and liquid flow rates in a multi-phase flow as claimed in  claim 1  wherein: 
       said multi-phase flow is contained within a pipeline;  
       said gas phase ultrasonic signal is transmitted by coupling said set of gas phase ultrasonic transducers to an exterior surface of said pipeline;  
       said set of gas phase ultrasonic transducers comprise at least one upstream gas phase ultrasonic transducer and at least one downstream gas phase ultrasonic transducer positioned on a common side of a central longitudinal axis of said pipeline;  
       said liquid phase ultrasonic signal is transmitted by coupling said set of liquid phase ultrasonic transducers to an exterior surface of said pipeline;  
       said set of liquid phase ultrasonic transducers comprise at least one upstream liquid phase ultrasonic transducer and at least one downstream liquid phase ultrasonic transducer positioned on a common side of said central longitudinal axis of said pipeline.  
     
     
       19. A method of determining gas and liquid flow rates in a multi-phase flow as claimed in  claim 1  wherein a value of said gas phase center frequency represents a compromise between unacceptable signal divergence at frequencies below or near 100 kHz and unacceptable signal attenuation at frequencies above or near 1 MHz. 
     
     
       20. A method of determining gas and liquid flow rates in a multi-phase flow as claimed in  claim 1  wherein said gas phase control parameters are established such that said gas phase center frequency is about 500 kHz and said gas phase bandwidth is about 300 kHz. 
     
     
       21. A method of determining gas and liquid flow rates in a multi-phase flow as claimed in  claim 1  wherein said gas phase control parameters are established such that said gas phase center frequency is above about 225 kHz and below about 1 MHz. 
     
     
       22. A method of determining gas and liquid flow rates in a multi-phase flow as claimed in  claim 1  wherein said gas phase control parameters are established such that said gas phase center frequency is about 500 kHz. 
     
     
       23. A method of determining gas and liquid flow rates in a multi-phase flow as claimed in  claim 1  wherein said gas phase control parameters are established such that said gas phase bandwidth is above about 225 kHz. 
     
     
       24. A method of determining gas and liquid flow rates in a multi-phase flow as claimed in  claim 1  wherein said gas phase control parameters are established such that said gas phase bandwidth is about 300 kHz. 
     
     
       25. A method of determining gas and liquid flow rates in a multi-phase flow as claimed in  claim 1  wherein said liquid phase control parameters are established such that said liquid phase center frequency is between about 0.5 MHz and about 5 MHz. 
     
     
       26. A method of determining gas and liquid flow rates in a multi-phase flow as claimed in  claim 1  wherein said liquid phase control parameters are established such that said liquid phase bandwidth is above about 300 kHz. 
     
     
       27. A method of determining gas and liquid flow rates in a multi-phase flow as claimed in  claim 1  wherein said liquid phase control parameters are established such that said liquid phase bandwidth is about 30% to about 80% of said value of said liquid phase center frequency. 
     
     
       28. A method of determining gas and liquid flow rates in a multi-phase flow as claimed in  claim 1  wherein said gas phase control parameters and said liquid phase control parameters are established such that said gas phase center frequency is less than said liquid phase center frequency. 
     
     
       29. A method of determining gas and liquid flow rates in a multi-phase flow as claimed in  claim 1  wherein: 
       said gas phase control parameters are established such that said gas phase center frequency is about 500 kHz and said gas phase bandwidth is about 300 kHz;  
       said liquid phase control parameters are established such that said liquid phase center frequency is between about 0.5 MHz and about 5 MHz and said liquid phase bandwidth is about 500 kHz.  
     
     
       30. A method of determining gas and liquid flow rates in a multi-phase flow contained within a pipeline utilizing a plurality of sets of gas phase ultrasonic transducers and a plurality of sets of liquid phase ultrasonic transducers positioned to direct ultrasonic signals through said multi-phase flow, said method comprising the steps of: 
       establishing a set of gas phase control parameters for said sets of said gas phase ultrasonic transducers such that said gas phase control parameters define a plurality of gas phase ultrasonic signals;  
       establishing a gas phase algorithm for determining a flow rate of a gaseous portion of said multi-phase flow, wherein  
       said gas phase control parameters define gas phase ultrasonic signals characterized by respective gas phase center frequencies and gas phase bandwidths and  
       said gas phase algorithm comprises at least one of a gas phase transit time algorithm and a gas phase cross correlation algorithm, and wherein said gas phase algorithm is established as said gas phase cross correlation algorithm over said gas phase transit time algorithm as a function of an amount of liquid in said multi-phase flow,  
       establishing a set of liquid phase control parameters for of plurality of sets of said liquid phase ultrasonic transducers such that said liquid phase control parameters define a plurality of liquid phase ultrasonic signals;  
       establishing a liquid phase algorithm for determining a flow rate of a liquid portion of said multi-phase flow, wherein  
       said set of liquid phase control parameters are established separately from said set of gas phase control parameters and  
       said liquid phase control parameters define liquid phase ultrasonic signals characterized by respective liquid phase center frequencies and liquid phase bandwidths and  
       said liquid phase algorithm comprises a liquid phase cross correlation algorithm;  
       coupling said set of gas phase ultrasonic transducers to an exterior surface of said pipeline, wherein said set of gas phase ultrasonic transducers comprise at least one upstream gas phase ultrasonic transducer and at least one downstream gas phase ultrasonic transducer;  
       controlling said gas phase ultrasonic transducers according to said gas phase control parameters so as to transit said gas phase ultrasonic signals;  
       analyzing said gas phase ultrasonic signals according to said gas phase algorithm with the aid of an ultrasonic data selection terminal, wherein said ultrasonic data selection terminal is controlled so as to establish a dwell time for each set of said plurality of sets of gas phase ultrasonic transducers;  
       coupling said set of liquid phase ultrasonic transducers to an exterior surface of said pipeline wherein said set of liquid phase ultrasonic transducers comprise at least one upstream liquid phase ultrasonic transducer and at least one downstream liquid phase ultrasonic transducer;  
       controlling said liquid phase ultrasonic transducers according to said liquid phase control parameters so as to transmit said liquid phase ultrasonic signals, wherein said liquid phase ultrasonic transducers are controlled separately from said gas phase ultrasonic transducers;  
       analyzing said liquid phase ultrasonic signals according to said liquid phase algorithm with the aid of said ultrasonic data selection terminal, wherein said ultrasonic data selection terminal is controlled so as to establish a dwell time for each set of said plurality of sets of liquid phase ultrasonic transducers; and  
       determining said gas and liquid flow rates based upon said analyses of said gas phase ultrasonic signals and said liquid phase ultrasonic signals.  
     
     
       31. A system for determining gas and liquid flow rates in a multi-phase flow contained within a pipeline, said system comprising: 
       a plurality of sets of gas phase ultrasonic transducers coupled to an exterior surface of said pipeline, wherein said set of gas phase ultrasonic transducers comprise at least one upstream gas phase ultrasonic transducer and at least one downstream gas phase ultrasonic transducer;  
       a plurality of sets of liquid phase ultrasonic transducers coupled to an exterior surface of said pipeline, wherein said set of liquid phase ultrasonic transducers comprise at least one upstream liquid phase ultrasonic transducer and at least one downstream liquid phase ultrasonic transducer; and  
       a flow rate analyzer, wherein said flow rate analyzer is programmed to  
       establish a set of gas phase control parameters for said plurality of sets of gas phase ultrasonic transducers such that said gas phase control parameters define a plurality of gas phase ultrasonic signals,  
       establish a gas phase algorithm for determining a flow rate of a gaseous portion of said multi-phase flow, wherein  
       said gas phase control parameters define gas phase ultrasonic signals characterized by respective gas phase center frequencies and gas phase bandwidths and  
       said gas phase algorithm comprises at least one of a gas phase transit time algorithm and a gas phase cross correlation algorithm, and wherein said gas phase algorithm is established as said gas phase cross correlation algorithm over said gas phase transit time algorithm as a function of an amount of liquid in said multi-phase flow,  
       establish a set of liquid phase control parameters for said plurality of sets of liquid phase ultrasonic transducers such that said liquid phase control parameters define a plurality of liquid phase ultrasonic signals;  
       establish a liquid phase algorithm for determining a flow rate of a liquid portion of said multi-phase flow, wherein  
       said set of liquid phase control parameters are established separately from said set of gas phase control parameters and  
       said liquid phase control parameters define liquid phase ultrasonic signals characterized by respective liquid phase center frequencies and liquid phase bandwidths and  
       said liquid phase algorithm comprises a liquid phase cross correlation algorithm;  
       control said gas phase ultrasonic transducers according to said gas phase control parameters so as to transmit said gas phase ultrasonic signals;  
       analyze said gas phase ultrasonic signals according to said gas phase algorithm with the aid of an ultrasonic data selection terminal, wherein said ultrasonic data selection terminal is controlled so as to establish a dwell time for each set of said plurality of sets of gas phase ultrasonic transducers;  
       control said liquid phase ultrasonic transducers according to said liquid phase control parameters so as to transmit said liquid phase ultrasonic signals, wherein said liquid phase ultrasonic transducers are controlled separately from said gas phase ultrasonic transducers;  
       analyze said liquid phase ultrasonic signals according to said liquid phase algorithm with the aid of said ultrasonic data selection terminal, wherein said ultrasonic data selection terminal is controlled so as to establish a dwell time for each set of plurality of sets of liquid phase ultrasonic transducers; and  
       determine said gas and liquid flow rates based upon said analyses of said gas phase ultrasonic signals and said liquid phase ultrasonic signals.  
     
     
       32. A method of determining gas and liquid flow rates in a multi-phase flow utilizing a set of gas phase ultrasonic transducers and a set of liquid phase ultrasonic transducers positioned to direct ultrasonic signals through said multi-phase flow, said method comprising the steps of: 
       establishing a set of gas phase control parameters and a gas phase algorithm for determining a flow rate of a gaseous portion of said multi-phase flow, wherein  
       said gas phase control parameters define a gas phase ultrasonic signal characterized by a gas phase center frequency and a gas phase bandwidth and  
       said gas phase algorithm comprises at least one of a gas phase transit time algorithm and a gas phase cross correlation algorithm;  
       establishing a set of liquid phase control parameters and a liquid phase algorithm for determining the flow rate of a liquid portion of said multi-phase flow, wherein  
       said set of liquid phase control parameters are established separately from said set of gas phase control parameters and  
       said liquid phase control parameters define a liquid phase ultrasonic signal characterized by a liquid phase center frequency and a liquid phase bandwidth and  
       said liquid phase algorithm comprises a liquid phase cross correlation algorithm, and wherein said gas phase algorithm is established as said gas phase cross correlation algorithm over said gas phase transmit time algorithm as an amount of liquid in said multi-phase flow increases;  
       controlling said gas phase ultrasonic transducers according to said gas phase control parameters so as to transmit said gas phase ultrasonic signal;  
       analyzing said gas phase ultrasonic signal according to said gas phase algorithm;  
       controlling said liquid phase ultrasonic transducers according to said liquid phase control parameters so as to transmit a liquid phase ultrasonic signal, wherein said liquid phase ultrasonic transducers are controlled separately from said gas phase ultrasonic transducers;  
       analyzing said liquid phase ultrasonic signal according to said liquid phase algorithm; and  
       determining said gas and liquid flow rates based upon said analyses of said gas phase ultrasonic signal and said liquid phase ultrasonic signal.